496 HO issues
 

Need help!!! 2006 35 Outlaw 496hos port engine having issues running. Boat will run perfect right off the trailer but after sitting in a cove for a few hours port engine will start but as soon as I put it under a load it just falls on its face. When given throttle, rpms jump all over and you hear and internal pop almost like a back fire. Boat has also done this after only running a few minutes so don't feel like it's a heat issue. Yesterday we coved out 6-8hrs after running about 20 minutes and it wouldn't run. Stopped scanned engines and then it ran fine all the way down the lake.

Things we have tried:
Scanned engine and no codes except for see below using Rinda TechMate Pro
Replaced spark plugs
Replaced IAC motor
Replaced fuel filter
Checked fuel pressure at idle and running 43psi
Compared outputs on both engines

When scanning I compared every single output and the only output that was not the same was the IAC % at idle. Problem port engine runs 20% at idle and starboard runs 0% at idle. Port ran about 50% at 3000 rpms Also, I did have a Map sensor code but it has since disappeared.

Anyone have this happen or have an idea what to look at?

Whats the battery voltage on each battery?

I would check your fuel injectors and rails. I am assuming 2006 motor so your cool fuel filter setup has been shedding all of its painted interior into the entire system for about 3 seasons now. Its very likely that you have clogged fuel system somewhere.

I just went through this same ordeal - Complete clean and refurb injectors, Clean and check fuel rails and new CoolFuel setups. Big expense but so is owning a 10k pound lawn ornament...

This is all advice given me own experience - you have not indicated Merc Alarm is screaming at you when you throttle up and it dies...so I am leaning fuel system.

I also had to replace my complete fuel system from the cool fuel and everything in between including the injectors. Find a merc. certified dealer and they can get all the parts under warranty and you just pay the labor. Do both motors at the same time. Even if its not the issue get it done because it will be a issue sooner or later. I was shocked they gave me thousands of dollars worth of parts for free. Merc. knows they sold a faulty system with paint on the inside of the fuel cool and it then peals off over time and clogs the rails, filters and injectors. The are doing the right thing so take advantage of it.

Imagine if only a knowledge source like BUP (John M) could dispense some quick advice on your issue given his overwhelming knowledge of this particular engine type? But alas....OSO needs to make that almighty dollar and since he has a marine mechanic business they gotta squeeze him for a membership.

I checked fuel pressure while having the issue and it was still 43psi but would not run.. It actually fluctuated a little higher when cutting out.. Up to about 47psi.. Would I still be seing the correct pressure during the issue if something was clogged up?

How old of a boat will they cover this on you think? Mine is a 2006 35 Baja

I did mine last year and it was also around the 2006 age.

Chances are yes because injectors can be clogged. Pressure is read before the injectors

Check your BUP...